#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define PI 3.1415926

int main(void) {
    double a,b;
    scanf("%lf%lf",&a,&b);
    srand(0);
    long long total=0;
    const int N=10000000;
    for(int i=0;i<N;i++)
    {
        double x=(double)rand()/RAND_MAX*2*a-a;
        double y=(double)rand()/RAND_MAX*2*b-b;
        if((x*x)/(a*a)+(y*y)/(b*b)<=1)
        {
            total++;
        }
    }
    double area=4*a*b*total/N;
    printf("area = %.6lf",area);
    return 0;
}
